Current-feeding to the electrodes of an electric arc furnace



1965 GUSTAV-ADOLF SIXEL 3,198,869

CURRENT-FEEDING TO THE ELECTRODES OF AN ELECTRIC ARC FURNACE Filed March 22, 1963 United States Patent Ofiice 3,198,869 Patented Aug. 3, 1965 3 198 869 CURRENT-FEEDING TO THE ELECTRODES OF AN ELECTRIC ARC FURNACE Gustav-Adolf Sixel, Dusseldorf, Kaiserswerth, Germany,

The present invention relates to a current feeding to the electrodes of an electric arc furnace.

Electric arc furnaces, for instance reduction furnaces and steel melting furnaces, are connected with a highvoltage conduit by providing an intermediate transformer. The current is fed to the electrodes on the low voltage side of the transformer by means of a conduit, which must be arranged partly flexible, in order to make possible the control movement of the electrodes and the tipping of the furnace or the swinging of the upper part of the furnace in order to charge the furnace. This flexible part of the conduit is subjected to electric losses and also to wear.

A shortening of the flexible part of the conduit and, thereby, a reduction of the stated drawbacks has been achieved already, such that the flexible part of the conduit has to compensate only the vertical control movements of the electrodes, while the tippingand swinging-movements of the furnace have been made possible by other means without interference with the current feeding, particularly such that the electrodes do not join the tipping and swinging movements of the furnace. Yet even by providing such measures, the flexible part of the conduit could not remove completely these known drawbacks.

It is one object of the present invention to provide a current feeding to the electrodes of an electric furnace wherein the flexible part of the conduit is made superfluous.

It is another object of the present invention to provide a current feeding to the electrodes of an electric furnace wherein the electrodes perform the vertical control movements, yet do not join the swinging movements of the furnace and in which the current is fed from the immovable part of the conduit to the part of the conduit joining the control movement of the electrodes by means of sliding contacts.

With these and other objects in view which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which:

FIGURE 1 is an elevation, partly in section, of an electric arc furnace with its current feeding means; and

FIGURE 2 is an elevation of parts of a sliding contact, partly in section.

Referring now to the drawing, the furnace pot 1 is tiltingly mounted on a tipping rocker 2. The heating of the furnace is brought about by electrodes 3, the supporting means of which are not shown. The high voltage current is fed to the transformer 5 by means of a conduit 4, from which it is fed as low voltage current by means of the conduit 6 into the part 7 of the conduit which is immovably secured parallel to the axes of the electrodes, that means disposed vertically and which is fed by means of the resilient current collector 8 to the conduit 9, and finally fed to the electrode 3 by means of an electrode holder 10.

The vertical conduit part 7 and the resilient current collector 8 are shown in FIG. 2 at an enlarged scale. The conduit part 7 comprises a hallow metal body, which is cooled by water, which is fed to and from the hollow metal body by means of pipes 12. The current collector 8 slides along the outer face of the hollow metal body 7, which current collector 8 is likewise designed as a water cooled hollow body and which is equipped inside with coal brushes 13 serving as sliding contacts, and which coal brushes 13 in turn slide in bushings 14 and are pressed onto the outer face of the hollow metal body 7 by means of springs 15. Sealing means 16 of conventional structure prevent the escape of the cooling water from the current collector 8. The feeding of the cooling water to and from the current collector 8 is brought about by means of pipes 17. Metal bellow 18 and 19 are secured to the top and to the bottom of the current collector 8, which metal bellows 18 and 19 surround the hollow metal body 7 and prevent the entrance of dust, which would interfere with the current feeding from the spring biased coal brushes 13 to the hollow metal body and conduit part 7 and also the sliding of these parts. During the vertical movements which are performed by the electrode 3, the current collector 8 slides with the coal brushes 13 along the vertical hollow metal body 7, whereby a current transfer from the hollow metal body 7 to the moved current collector 8 takes place, without necessity that the drawbacks which are inherent in a flexible conduit part, have to be taken in stride. A plurality of coal brushes 13 are suitably provided for each electrode, in order to secure an improved current transfer.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. Apparatus for feeding current to the electrodes of an electric arc furnace comprising a furnace pot,

electrodes movable vertically into said furnace pot,

current feeding means to said electrodes including a first immovable conduit part and a second conduit part joining the vertical movements of said electrodes, and

contact brushes secured to said second conduit part and slidingly engaging said first conduit part during the vertical movement of said second conduit part, in order to feed current from said first immovable conduit part to said second movable conduit part.

2. The current feeding apparatus, as set forth in claim 1, wherein said first conduit part, engaged by said contact brushes,

is disposed parallel to said electrodes.

3. The current feeding apparatus, as set forth in claim 1, which includes means for connecting said contact brushes with said electrodes for joint vertical movements therewith.

4. The current feeding apparatus, as set forth in claim 1, which includes means for cooling said contact brushes.

L 5. The current feeding apparatus, as set forth in claim 1, which includes means for cooling said first conduit part feeding current to said contact brushes. 6. The current feeding apparatus, as set forth in claim 1, which includes means for protecting said contact brushes and the faces of said first conduit part engaging said contact brushes from dust. 7. The current feeding apparatus, as set forth in claim 6, wherein said protecting means comprises bellows disposed above and below said contact brushes and secured to said .41. second conduit part and surrounding said fist conduit part.

References Cited by the Examiner UNITED STATES PATENTS 404,244 5/89 Atwood l3l5 X FOREIGN PATENTS 244,171 3/ 12 Germany.

RICHARD M. WOOD, Primary Examiner. JOSEPH V. TRUHE, Examiner. 

1. APPARATUS FOR FEEDING CURRENT TO THE ELECTRODES OF AN ELECTRIC ARC FURNACE COMPRISING A FURNACE POT, ELECTRODES MOVABLE VERTICALLY INTO SAID FURNACE POT, CURRENT FEEDING MEANS TO SAID ELECTRODES INCLUDING A FIRST IMMOVABLE CONDUIT PART AND A SECOND CONDUIT PART JOINING THE VERTICAL MOVEMENTS OF SAID ELECTRODES, AND CONTACT BRUSHES SECURED TO SAID SECOND CONDUIT PART AND SLIDINGLY ENGAGING SAID FIRST CONDUIT PART DURING THE VERTICAL MOVEMENT OF SAID SECOND CONDUIT PART, IN ORDER TO FEED CURRENT FROM SAID FIRST IMMOVABLE CONDUIT PART TO SAID SECOND MOVABLE CONDUIT PART. 